humboldt state university in northern california is holding interdisciplinary studies right now focusing on medical marijuana. it's being run by different professors and lecturers. medical marijuana's a hot topic now as more states allow its use and two states, as you know, they've approved the drug for recreational use. so here's a question -- would you let a first or second grader or any child use medical marijuana? some family members in oregon say yes. 7-year-old any kyla comstock has leukemia. she's a registered medical marijuana patient. her mom gives her the drug every day. not surprisingly, there are some, including her father, who have concerns about this. after all, she's 7 years old. dr. sanjay gupta joins us with more. and we wanted to get your opinion on this. >> well, i mean, the first question a lot of people ask is, is this even safe to do. and this ends up being the crux of questions surrounding marijuana. what is hard from a purely scientific standpoint is that it's an illegal drug in the united states. so it's hard to do studies on a drug that's illegal. you often look